In natural teeth the periodontal ligament functions as a cushion between tooth and jawbone, absorbing impact force and uniformly transferring occlusal forces to surrounding bone. The distribution of the force depends on micro movement induced by the periodontal ligament. Due to lack of periodontal ligament, dental implant has to directly bond to bone, causing non-uniform stress distribution in bone which might lead to implant failure (Quirynen 1992). Because of the lack of micro movement of implants, most of the force distribution is concentrated at the crest of the ridge. Vertical forces at the bone interface are concentrated at the crestal regions, and lateral forces increase the magnitude of the crestal force distribution.
US 2010/0304334 A1 discloses a dental implant system comprising an implant having a well and an abutment having a post shaped to be received in the tapered well, and in one embodiment shown thereof the implant and the abutment are jointed one to the other with a retentive elastomeric product, enabling an artificial tooth supported by the abutment to move in a fashion similar to that of a natural tooth.